The present invention relates to vehicles. In particular, an apparatus for determining and providing a cable lash compensation for a cruise control cable is disclosed.
Once initialized, a cruise control system maintains a selected vehicle speed until the system is disabled or its setting is changed. The cruise control system employs a cable that is secured to a throttle cam of a throttle assembly at one end and a mechanism for applying a force to the cable at the other end. Once the cruise control system of a vehicle has been set for a given speed the mechanism receives a command or plurality of commands to either pull the cable and increase the engine RPMs or maintain the cable""s current position or allow the biasing spring of the throttle cam to decrease the engine RPMs.
In order to prevent a cruise control system from having an unnecessary delay in executing the commands of the cruise control system it is desirable to anticipate the required throttle position based upon a given vehicle speed setting. This is particularly desirable in applications when the cruise control system is first initialized.
However, driving conditions are constantly changing and an initial setting of a cruise control system for a given vehicle speed rarely has the identical throttle position. For example, and if a vehicle is traveling up a hill, the system will require a greater throttle position than the same vehicle traveling on a level road or lower incline. In addition, the same is true for a vehicle traveling down an incline as opposed to a level road. Moreover, the vehicles loads may also vary due to the number of passengers and whether the vehicle is towing an object such as a boat or trailer.
Accordingly, there is a need for a cruise control system wherein the system can anticipate variations in the system and respond to them accordingly.
In an exemplary embodiment, the control algorithm of a cruise control module is modified to include a lash learn process wherein the designed absolute value of how much cable is allowed is adjusted for lash that is encountered by the system.
In another embodiment, the lash learn process or algorithm sets a limit for the maximum lash that can be learned and the maximum lash that can be changed for each adjustment.
The above-described and other features and advantages of the present invention will be appreciated and understood by those skilled in the art from the following detailed description, drawings, and appended claims.